Some differences from the anime, big and small:
>the dorm is a modern apartment complex presumably combined with the editing department
>Nijino-sensei isn't introduced until Volume 2
>the dorm matron being a former yuri mangaka is mentioned earlier, though only alluded to thus far in episode 5
>additional minor teasing of Ruki/Kaos with Kaos being Ruki's phone lock screen, and Kaos's accumulation of many Ruki-like figures
>Tsubasa thinks Koyume hates her due to misunderstanding the latter's crush-associated embarrassment throughout Volume 1; Koyume attempts to provide assistant/maid service to make up with her